金银/氮化钛表面增强拉曼基底制备及对烟酸的定量检测

表面增强拉曼光谱技术对分子具有特异性识别以及快速无损检测的能力，使其在药物检测方面具有重大的潜力。通过贵金属和氮化钛之间协同作用，使复合基底具有较高的SERS性能，提供了一种基于SERS技术的药物检测方法。采用电化学沉积及自组装法，制备出贵金属/氮化钛复合薄膜。研究表明，在复合薄膜中存在面心立方晶型TiN、金属单质Au和Ag三种物相；电子显微镜显示平均粒径分别为90和50 nm的金属Au和Ag颗粒均匀分布在TiN薄膜表面；基底的紫外-可见吸收图谱中出现了贵金属金与银纳米颗粒及TiN薄膜三者的特征等离子体共振吸收峰。以该复合薄膜为SERS基底，对烟酸溶液进行拉曼检测。结果显示，贵金属/氮化钛复合薄膜对烟酸具有显著的SERS效应，最低检测浓度为10-5 mol·L-1，对1 033 cm-1处烟酸拉曼信号强度及浓度取对数，发现两者间呈一定线性关系，其R2为0.969，得益于TiN，Au和Ag之间可发生表面等离子体共振引起电磁场增强，以及电荷转移效应。研究还发现，烟酸通过COO-基团垂直吸附在贵金属/氮化钛基底表面；在酸性环境下，烟酸N原子质子化主要以阳离子N＋H（Ⅰ）形式存在；在碱性环境时，主要以阴离子COO-（Ⅲ）形式存在。绞股蓝总甙溶液中模拟烟酸非法添加，该复合基底对其最低的拉曼检测浓度是10-5 mol·L-1，为现场快速检测非法添加药物提供了新途径。

Preparation of Gold/Silver/Titanium Nitride Suface-Enhanced Raman Substrate and Its Effect on Nicotinic Acid Quantitative Detection

The surface-enhanced Raman spectroscopy technology has specific recognition of molecules and rapid non-destructive detection capabilities, making it great potential in drug detection. In this study, drug detection research based on novel metal/titanium nitride composite substrate as SERS active substrate was carried out. Due to the synergy between the novel metal and titanium nitride, the composite substrate has high SERS performance, providing a drug detection method based on SERS technology. Electrochemical deposition and self-assembly methods were used to prepare novel metal/titanium nitride composite film. There are three kinds of phases: face-centered cubic crystal TiN, metal Au and Ag in the composite film. The electron microscopy showed that metal Au and Ag particles with a mean particle size of 90 and 50 nm were evenly distributed on TIN film’s surface. For this reason, the characteristic plasmon resonance absorption peaks of the novel metal gold and silver nanoparticles and TiN thin film appeared in the ultraviolet-visible absorption spectra of the thin film. Using the composite film as the SERS substrate, Raman detection was performed on the nicotinic acid solution. The results show that the novel metal/titanium nitride composite film has a significant SERS effect. The logarithm of the Raman signal intensity and nicotinic acid concentration at 1 033 cm-1 indicated a certain linear relationship between the two, the linear correlation coefficient was 0.969, and the minimum detection concentration of nicotinic acid was 10-5 mol·L-1. This is due to the effect of charge transfer and the enhancement of the electromagnetic field caused by the surface plasmon resonance between the particles of TiN, Au and Ag. It was also found that nicotinic acid was vertically adsorbed on the novel metal/titanium nitride substrate’s surface through the COO- group. When in an acidic environment, the protonation of nicotinic acid N atom mainly existed in cation N+H(Ⅰ). In an alkaline environment, it mainly existed in the form of anion COO-(Ⅲ). In addition, for the illegal addition of nicotinic acid in the gypenoside solution, the lowest Raman detection concentration of the composite substrate is 10-5 mol·L-1, which provides a new way for the rapid detection of illegally added drugs on site.